You can armor a small list of animals with either iron or steel armor here. This will both increase their defensive as well as offensive capabilities. Quite a lot, actually. You need iron or steel bars and mechanisms for this.

First you need to bring the animal to the kennels. Simply make a pasture on top of the workshop and assign the wanted animals there. You can do as many as you want in one go. Then run the reaction, and one of the creatures will transform into its armored version.

If an armored creature is butchered, it will also create an inedible metal part. These parts can be recycled to gain back a bit of the metal.

WARNING: Armored animals do not breed. Due to game mechanics they would give birth to already armored children. Don't armor all your warbeasts if you still want to breed them.